Bhand Sunil, Mishra Geetesh K
Biosensor Lab, Department of Chemistry, BITS, Pilani-K.K., Birla Goa Campus, Goa, 403726, India.
Methods Mol Biol. 2017;1572:263-276. doi: 10.1007/978-1-4939-6911-1_18.
An electrochemical quartz crystal nanobalance (EQCN), which provides real-time analysis of dynamic surface events, is a valuable tool for analyzing biomolecular interactions. EQCN biosensors are based on mass-sensitive measurements that can detect small mass changes caused by chemical binding to small piezoelectric crystals. Among the various biosensors, the piezoelectric biosensor is considered one of the most sensitive analytical techniques, capable of detecting antigens at picogram levels. EQCN is an effective monitoring technique for regulation of the antibiotics below the maximum residual limit (MRL). The analysis of antibiotic residues requires high sensitivity, rapidity, reliability and cost effectiveness. For analytical purposes the general approach is to take advantage of the piezoelectric effect by immobilizing a biosensing layer on top of the piezoelectric crystal. The sensing layer usually comprises a biological material such as an antibody, enzymes, or aptamers having high specificity and selectivity for the target molecule to be detected. The biosensing layer is usually functionalized using surface chemistry modifications. When these bio-functionalized quartz crystals are exposed to a particular substance of interest (e.g., a substrate, inhibitor, antigen or protein), binding interaction occurs. This causes a frequency or mass change that can be used to determine the amount of material interacted or bound. EQCN biosensors can easily be automated by using a flow injection analysis (FIA) setup coupled through automated pumps and injection valves. Such FIA-EQCN biosensors have great potential for the detection of different analytes such as antibiotic residues in various matrices such as water, waste water, and milk.
电化学石英晶体纳米天平（EQCN）能够对动态表面事件进行实时分析，是分析生物分子相互作用的宝贵工具。EQCN生物传感器基于质量敏感测量，可检测与小型压电晶体发生化学结合时引起的微小质量变化。在各种生物传感器中，压电化学传感器被认为是最灵敏的分析技术之一，能够检测皮克级别的抗原。EQCN是一种用于监测抗生素残留量是否低于最大残留限量（MRL）的有效技术。抗生素残留分析需要具备高灵敏度、快速性、可靠性和成本效益。为了进行分析，一般方法是通过在压电晶体顶部固定生物传感层来利用压电效应。传感层通常包含对要检测的目标分子具有高特异性和选择性的生物材料，如抗体、酶或适配体。生物传感层通常通过表面化学修饰进行功能化。当这些生物功能化的石英晶体暴露于特定的目标物质（如底物、抑制剂、抗原或蛋白质）时，会发生结合相互作用。这会导致频率或质量变化，可用于确定相互作用或结合的物质的量。通过使用与自动泵和进样阀相连的流动注射分析（FIA）装置，EQCN生物传感器可以很容易地实现自动化。这种FIA-EQCN生物传感器在检测不同分析物方面具有巨大潜力，例如在水、废水和牛奶等各种基质中的抗生素残留。
